Mask, substrate with light reflective film, method for manufacturing light reflective film, liquid crystal display device, and electronic apparatus

ABSTRACT

A substrate is provided with a light reflective film including a base and a reflective layer, in which a plurality of concave portions or convex portions formed on the surface of the base are randomly arranged in the plane direction in 100 to 2,000 RGB dot units or a whole screen unit, are formed using a mask in which light transmissive or non-transmissive portions are randomly arranged in the plane direction in 100 to 2,000 RGB dot units or the whole screen unit.

BACKGROUND

[0001] 1. Technical Field of the Invention

[0002] The present invention relates to a mask, a substrate with a lightreflective film, a method for manufacturing a light reflective film, anoptical display device, and an electronic apparatus, and morespecifically, it relates to a mask for manufacturing a substrate with alight reflective film generating few interference fringes, a substratewith a light reflective film formed by using the mask, a method formanufacturing a light reflective film, an optical display device havinga light reflective film on which hardly any interference fringes aregenerated, and an electronic apparatus having a light reflective film onwhich hardly any interference fringes are generated.

[0003] 2. Related Art

[0004] As widely known, liquid crystal display devices are widely usedas display devices in various electronic apparatuses because of theirability to reduce thickness and power consumption. Such liquid crystaldisplay devices normally have a configuration in which a liquid crystalis injected between a pair of glass substrates and the peripheral edgesof the substrates are sealed by a sealant. An electronic apparatushaving such a liquid crystal display device therein adopts aconfiguration in which a protective plate is provided on the viewingside of the liquid crystal display device, that is, the side a viewerobserves the display thereon, in order to protect the liquid crystaldisplay device against external impacts. The protective plate is aplate-shaped member which is normally made of a material having lighttransmittance characteristics, for example, transparent plastic, etc.

[0005] However, in such protective plate, it is difficult to make itssurface facing the liquid crystal display device completely smooth, andfine concave portions or convex portions exist on the surface in manycases. Therefore, in the case of providing such a protective plate onthe liquid crystal display device, there is a problem that the displayquality is greatly deteriorated due to the fine concave portions orconvex portions on the surface.

[0006] One reason for the deterioration of the display quality is thatthe gap between the substrate at the viewing side and the protectiveplate in the liquid crystal display device is uneven due to theconcavities or convexities existing on the surface of the protectiveplate. That is, corresponding to the unevenness of the gap, interferenceoccurs when light coming from the liquid crystal display device passesthrough the protective plate and as a result, interference fringes aregenerated. It is presumed that the display quality is deterioratedbecause the generated interference fringes and the display images aremixed.

[0007] A reflective liquid crystal display device 400 as shown in FIG.25 is disclosed in Japanese Unexamined Patent Application PublicationNo. 6-27481; a transflective type liquid crystal display device 500 asshown in FIG. 26 is disclosed in Japanese Unexamined Patent ApplicationPublication No. 11-281972. In the respective devices, a plurality ofconcave or convex structures 404 a, 404 b (504 a, 504 b) havingdifferent heights from each other are provided to decrease theoccurrence of interference fringes, and a high-molecular resin film 405(505) is formed thereon, and a continuous wave-shaped reflectiveelectrode 409 (509) is formed thereon.

[0008] In addition, a manufacturing process of a liquid crystal displaydevice having such a reflective electrode is illustrated on FIG. 27, forexample. First, as shown in FIG. 27(a), a photoresist film 602 is formedon the overall surface of a glass substrate 600, and then, as shown inFIG. 27(b), the photoresist film 602 is exposed through a pattern 604comprising a plurality of circles of different diameters. Then, as shownin FIG. 27(c), it is developed, and a plurality of concave or convexportions 606 a, 606 b, each having different height and angle, areprovided. Then, by heating the concave or convex portions and softeningthe angled portion of the concave or convex portions as shown in FIG.27(d), angle-removed concave or convex portions 608 a, 608 b are formed.As shown in FIG. 27(e), the space 610 between the concave or convexstructures is filled with a predetermined amount of high-molecular resin620 to make a continuous layer having the wave-shaped surface. Inaddition, a wave-shaped reflective electrode 624 is formed on thehigh-molecular resin film 620 by using a stacking method such as asputtering method.

[0009] The reflective liquid crystal display device or transflectiveliquid crystal display disclosed in Japanese Unexamined PatentApplication Publication No. 6-27481, employs a mask pattern on which aplurality of circles of different diameters, are aligned uniformly ornon-uniformly in part, to provide a structure having a plurality ofconcavities or convexities of different heights by using ultravioletexposure and development. However, it is difficult to adjust the heightprecisely to effectively prevent the light interference because of theunevenness of the coating thickness, or the like. In addition, since areflective electrode is formed on the structure having the plurality ofconcaves or convexes of different heights, there often occurs a breakingof wire or short circuit, too. In addition, the disclosed method formanufacturing a light reflective film involves many processing steps andmanagement items to be processed, which results in many problems in themanufacture.

[0010] Therefore, according to the light reflective film disclosed inJapanese Unexamined Patent Application Publication No. 6-27481, it isnot only difficult to prevent the occurrence of interference fringeseffectively, but also difficult to manufacture such light reflectivefilm stably and effectively.

[0011] Thus, there have been proposed methods for manufacturing theabove-described reflective-type liquid crystal display device or theabove-described transflective type liquid crystal display device using amask in which light transmissive or non-transmissive portions arerandomly arranged. Although the above-proposed methods reduce theoccurrence of the interference fringe, a new problem has been found thatstains of various shapes are seen on a screen, thereby causingremarkable deterioration of display quality.

[0012] The present inventors have extensively studied the abovedescribed problems and found that a light reflective film whichgenerates few interference fringes while suppressing the occurrence ofvarious-shaped stains when incorporated into a liquid crystal displaydevice can be achieved by providing a plurality of concave portions orconvex portions on a base at random and in a specific arrangement.

[0013] Therefore, it is an object of the present invention to provide amask used for manufacturing a substrate with a light reflective filmwith reduced occurrence of the interference fringe, a substrate with alight reflective film obtained using the mask, a method formanufacturing the light reflective film, a liquid crystal displayprovided with the light reflective film, and an electronic apparatuscomprising the light reflective film.

SUMMARY

[0014] In accordance with one aspect of the present invention, the aboveand other objects can be accomplished by the provision of a mask formanufacturing a substrate with a light reflective film, wherein lighttransmissive or non-transmissive portions are randomly arranged in theplane direction in 100 to 2,000 RGB dot units or a whole screen unit.

[0015] That is, since the light transmissive or non-transmissiveportions are randomly arranged, the substrate provided with the lightreflective film exhibits excellent light scattering effect andeffectively prevents the occurrence of the interference fringe.

[0016] On the other hand, the occurrence of stains of various shapes dueto such random arrangement of the light transmissive or non-transmissiveportions can be remarkably reduced by arranging them in units of morethan a predetermined number of RGB dots of the liquid crystal displaydevice using the substrate with the light reflective film.

[0017] The reason why the plane arrangement of the light transmissive ornon-transmissive portions is controlled is that there are two types ofphotosensitive resins to be used for making the base of the lightreflective film; one is a positive type which is photolyzed and becomessoluble in a developing agent at its area on which light having passedthe light transmissive portions is radiated; and the other is a negativetype, and its area radiated by the light having passed the lighttransmissive portions is exposed and becomes insoluble in the developingagent.

[0018] In making the mask of the present invention, preferably, a randompattern of light transmissive or non-transmissive portions for 3 to 12RGB dots and randomly arranged as it is or after being divided, therebyto form the light transmissive or non-transmissive portions in 100 to2,000 dot units or a whole screen unit.

[0019] Thereby, even with relatively little information regarding thepatterns of the light transmissive portions or the lightnon-transmissive portions, the mask having a large area can be easilyformed in a short time.

[0020] In making the mask of the present invention, preferably, astripe-shaped random pattern of light transmissive or non-transmissiveportions in a row direction or in a column direction is formed and isrepeated in a plurality of lines, to thereby form the light transmissiveor non-transmissive portions.

[0021] Thereby, even with little information, it is possible to easilyform the random pattern with desirable reflectivity as a whole in ashort time. Further, it is possible to obtain the random patterns ofdesirable reflectivity as a whole with good reproducibility by repeatingpredetermined units of random patterns in horizontal or verticaldirection.

[0022] In making the mask of the present invention, preferably, thediameters of the light transmissive or non-transmissive portions are anyvalue within the range of 3 to 15 m.

[0023] Thereby, it is possible to effectively manufacture a substratewith a light reflective film to reduce the occurrence of an interferencefringe. This is because when the substrate with the light reflectivefilm is manufactured, in case that the light transmissive ornon-transmissive portions have such diameters, it is possible toprecisely control the planar shapes and the arrangement patterns of theportions using an exposure process. As a result, it is possible toreliably scatter light in the substrate with the light reflective film,thereby effectively preventing the occurrence of an interference fringe.

[0024] In making the mask of the present invention, preferably, thelight transmissive or non-transmissive portions have different diametersto form a plurality of kinds of light transmissive or non-transmissiveportions.

[0025] Thereby, it is possible to effectively manufacture a substratewith the light reflective film to reduce the occurrence of theinterference fringe. That is, when the substrate with the lightreflective film including a plurality of concave portions or convexportions is manufactured, the concave portions or convex portions can bearranged more diversely due to the existence of the plurality of concaveportions or convex portions of different diameters. Accordingly, it ispossible to properly scatter light in the obtained substrate with thelight reflective film, thereby effectively preventing the occurrence ofan interference fringe.

[0026] In case that the light transmissive or non-transmissive portionshave different diameters, preferably, the diameter of at least one ofthe portions is 5 μm or more. In case that every portion has a diameterof below 5 μm and has a circle or polygonal shape, when the substratewith the light reflective film is manufactured, light is oftenexcessively scattered, and the amount of reflected light in thesubstrate with the light reflective film may be remarkably reduced.

[0027] In accordance with a further aspect of the present invention,there is provided a substrate with a light reflective film including abase and a reflective layer, wherein a plurality of concave portions orconvex portions formed on the surface of the base are randomly arrangedin the plane direction in 100 to 2,000 RGB dot units or a whole screenunit.

[0028] Thereby, it is possible to prevent the occurrence of theinterference fringe by the random arrangement of the concave portions orconvex portions.

[0029] Further, since random patterns formed of the concave portions orconvex portions are arranged in 100 to 2,000 RGB dot units or the wholescreen unit, it is possible to reduce the occurrence of stains ofvarious shapes.

[0030] In making the mask of the present invention, preferably, astripe-shaped random pattern of concave portions or convex portions in arow direction or in a column direction is formed, and repeated in aplurality of lines, to thereby form the plurality of concave or convexportions.

[0031] Thereby, even with little information, it is possible to form therandom pattern of desirable reflectivity as a whole in a short time.Further, it is possible to obtain the random pattern of generallydesirable reflectivity as a whole with good reproducibility by repeatinga predetermined unit of the random pattern in a horizontal or verticaldirection.

[0032] In making the substrate with the light reflective film of thepresent invention, preferably, the diameters of the concave portions orconvex portions are any value within the range of 3 to 15 μm.

[0033] Thereby, it is possible to precisely control the planar shapesand the arrangement patterns of the concave portions or convex portionsusing an exposure process. Further, it is possible to properly scatterlight so as to effectively prevent the occurrence of an interferencefringe.

[0034] In making the substrate with the light reflective film of thepresent invention, preferably, the heights of the convex portions or thedepths of the concave portions are any value within the range of 0.1 to10 μm.

[0035] Thereby, it is possible to precisely control the planar shapesand the arrangement patterns of the concave portions or convex portionsusing an exposure process. Further, in case that the substrate with thelight reflective film is used in liquid crystal display devices, etc.,it is possible to properly scatter light so as to effectively preventthe occurrence of an interference fringe.

[0036] In making the substrate with the light reflective film of thepresent invention, preferably, the concave portions or convex portionshave different diameters to form a plurality of kinds of lighttransmissive or non-transmissive portions.

[0037] Thereby, in case that the substrate with the light reflectivefilm is used in the liquid crystal display device, it is possible toarrange the concave portions or convex portions more diversely. Further,it is possible to properly scatter light so as to effectively preventthe occurrence of the interference fringe.

[0038] In making the substrate with the light reflective film of thepresent invention, preferably, the base includes a first base and asecond base formed from the bottom, the first base includes a pluralityof concave portions or convex portions, and the second base includes areflective layer thereon.

[0039] Thereby, in the case that the substrate with the light reflectivefilm is used in a liquid crystal display device, it is possible to formthe reflective layer having a relatively gently curved surface bydisposing the continuously formed second base thereon, thereby furthereffectively preventing the occurrence of the interference fringe.

[0040] Another aspect of the present invention provides a method formanufacturing a substrate with a light reflective film including a baseand a reflective film, comprising the steps of: (a) forming a first baseincluding a plurality of concave portions or convex portions arrangedrandomly by performing an exposure process on an applied photosensitiveresin using a mask in which light transmissive or non-transmissiveportions are randomly arranged in the plane direction in 100 to 2,000RGB dot units or a whole screen unit; (b) forming a second baseincluding a plurality of continuous concave portions or convex portionsby applying a photosensitive resin on the surface of the first base andsubsequently performing an exposure process on the appliedphotosensitive resin; and (c) forming a reflective layer on the surfaceof the second base.

[0041] Thereby, it is possible to form the reflective layer with acomparatively gently curved surface by the first base including theconcave portions or convex portions and the continuous second base. Theabove method can efficiently provide the substrate with the lightreflective film which is easy to manufacture and reduces the occurrenceof an interference fringe when used in liquid crystal display devices,etc.

[0042] Still another aspect of the present invention provides an opticaldisplay device comprising an optical element sandwiched betweensubstrates and a light reflective film formed on the substrate providedopposite to the viewing side of the optical element, wherein the lightreflective film includes a base and a reflective layer, and a pluralityof concave portions or convex portions formed on the surface of the baseare randomly arranged in the plane direction in 100 to 2,000 RGB dotunits or a whole screen unit.

[0043] Thereby, since the light reflective film is properly scattered,it is possible to effectively prevent the occurrence of an interferencefringe in the optical display device.

[0044] Further, since random patterns comprising the concave portions orconvex portions are arranged in 100 to 2,000 RGB dot units or the wholescreen unit, it is possible to reduce the occurrence of stains ofvarious shapes.

[0045] In making the optical display device of the present invention,preferably, a light scattering film is provided on the substrate at theviewing side of the optical display device.

[0046] By using the light reflective film in combination with the lightscattering film, it is possible to reduce the occurrence of stains ofvarious shapes.

[0047] In making the optical display device of the present invention,preferably, a protective plate is provided on the viewing side of theoptical element.

[0048] Thereby, it is possible to increase the mechanical strength ofthe optical display device, while improving the appearance of theoptical display device.

[0049] Yet another aspect of the present invention provides anelectronic apparatus including an optical display device with a lightreflective film, wherein the light reflective film includes a base and areflective layer, and a plurality of concave portions or convex portionsformed on the surface of the base are randomly arranged in the planedirection in 100 to 2,000 RGB dot units or a whole screen unit.

[0050] Accordingly, such a light reflective film reflects lightproperly, and can reduce the occurrence of stains of various shapes andeffectively prevent the occurrence of an interference fringe in theelectronic apparatus.

[0051] Furthermore, the electronic apparatus comprising such a lightreflective film has a comparatively flat surface so that it can realizea good appearance even additionally provided with a light scatteringfilm and protective plate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052]FIG. 1 is a plan view for explaining a mask in accordance with thepresent invention.

[0053]FIG. 2 is a plan view for explaining a mask in which lighttransmissive or non-transmissive portions are randomly arranged in theplane direction by one pixel unit (RGB: 3 dots).

[0054]FIG. 3 is a plan view for explaining a mask in which lighttransmissive or non-transmissive portions are randomly arranged in theplane direction by two pixel unit (RGB: 6 dots).

[0055]FIG. 4 is a plan view for explaining a mask in which lighttransmissive or non-transmissive portions are randomly arranged in theplane direction by three pixel unit (RGB: 12 dost).

[0056]FIG. 5 is a plan view for explaining a mask in which lighttransmissive or non-transmissive portions are randomly arranged by onerow line unit.

[0057]FIG. 6 is a cross-sectional view of a light reflective filmincluding first and second substrates.

[0058]FIGS. 7a and 7 b show plan and cross-sectional views of a lightreflective film including asymmetrical and substantially teardrop-shapedconvex portions.

[0059]FIG. 8 is a graph illustrating the relationship between the amountof light to be displayed and the viewing angle of light.

[0060]FIG. 9 is a cross-sectional view of a light reflective film withopenings.

[0061]FIGS. 10a-10 e illustrate the process for manufacturing a lightreflective film.

[0062]FIG. 11 is a flow chart of the process for manufacturing the lightreflective film.

[0063]FIG. 12 is a cross-sectional view for explaining the configurationa light reflective film electrically connected to a TFT element.

[0064]FIG. 13 is a cross-sectional view showing the constitution of apassive matrix liquid crystal display device.

[0065]FIG. 14 is a cross-sectional view showing the constitution ofanother liquid crystal display device.

[0066]FIG. 15 is a perspective view showing the constitution of apersonal computer as one example of electronic apparatus.

[0067]FIG. 16 is a perspective view showing the constitution of a mobilephone as another example of electronic apparatus.

[0068]FIG. 17 shows plan and cross-sectional views of a substrate with alight reflective film including substantially cone-shaped concaveportions.

[0069]FIG. 18 shows plan and cross-sectional views of a substrate with alight reflective film including asymmetrical, substantiallyteardrop-shaped concave portions.

[0070]FIG. 19 shows plan and cross-sectional views of a substrate with alight reflective film including pyramid-shaped concave portions.

[0071]FIG. 20 shows plan and cross-sectional views of a substrate with alight reflective film including concave portions whose horizontalcross-section is an arc shape with a small radius of curvature, andwhose vertical section is an arc shape with a large radius of curvature.

[0072]FIG. 21 shows plan and cross-sectional views of a substrate with alight reflective film including concave portions whose horizontalcross-section is a substantially rectangle, and whose vertical sectionis a pyramid.

[0073]FIG. 22 is an exploded perspective view of a TFD type liquidcrystal display device.

[0074]FIG. 23 is a partial cross-sectional view of the TFD type liquidcrystal display device.

[0075]FIG. 24 is a partial perspective view of the TFD type liquidcrystal display device.

[0076]FIG. 25 is a cross-sectional view showing the constitution of aconventional liquid crystal display device.

[0077]FIG. 26 is a cross-sectional view showing the constitution ofanother conventional liquid crystal display device.

[0078]FIGS. 27a-27 e illustrate the process for manufacturing aconventional liquid crystal display device.

DETAILED DESCRIPTION

[0079] Now, preferred embodiments of the present invention will bedescribed in detail with reference to the drawings. It should beunderstood that the following embodiments are only for illustrating thepresent invention, and do not intend to limit the present invention inany way. Those skilled in the art will appreciate that variousmodifications are possible without departing from the scope and spiritof the invention.

[0080] First embodiment

[0081] In a first embodiment of the present invention, as shown in FIG.1, there is provided a mask 10 to manufacture a substrate with a lightreflective film. The mask 10 includes light transmissive ornon-transmissive portions randomly arranged in the plane direction in100 to 2,000 RGB dot units or the whole screen unit.

[0082] The random arrangement of the light transmissive ornon-transmissive portions simply means a disorderly arrangement of thelight transmissive or non-transmissive portions. More exactly, it meansthat in case that the mask is cut into a plurality of unit areas and thecut unit areas of the mask are stacked, patterns of the cut unit areasare completely different, or partially similar but not completely.

[0083] 1. Light transmissive or non-transmissive part

[0084] (1) Shape

[0085] Preferably, the light transmissive or non-transmissive portionsof the mask have planar shapes of independent or partially overlappedcircles (including ovals) or polygons, or either thereof.

[0086] The reason is that when an exposure process is performed on themask in order to manufacture the light reflective film, a resin can havea complicated structure of concave or convex portions by making theplane shapes of the light transmissive or non-transmissive portionscircular or polygonal. This is also because the circular or polygonalshapes are basic figures, so the manufacture of the mask itself becomeseasier. Incidentally, preferred polygons include tetragon, pentagon,hexagon, octagon, etc.

[0087] (2) Diameter and pitch

[0088] Preferably, the diameters of the light transmissive ornon-transmissive portions of the mask are any value within the range of3 to 15 μm.

[0089] The reason is that when the diameters of the light transmissiveor non-transmissive portions are below 3 μm, it is difficult toprecisely control the planar shapes and the arrangement patterns ofconcave portions or convex portions, when an exposure process ispreformed so as to manufacture the light reflective film. This is alsobecause when the diameters of the light transmissive or non-transmissiveportions are below 3 μm, it is sometimes difficult to manufacture themask itself.

[0090] On the other hand, when the diameters of the light transmissiveor non-transmissive portions exceed 15 μm, it is difficult to properlyscatter light by the obtained light reflective film, therebydeteriorating the scattering property and the reflectivity.

[0091] Accordingly, preferably, the diameters of the light transmissiveor non-transmissive portions of the mask are any value within the rangeof 3 to 15 μm, more preferably, within the range of 6 to 12 μm.

[0092] Preferably, the diameter of at least one of the lighttransmissive or non-transmissive portions of the mask is 5 μm or more.That is, in case that the diameters of the light transmissive ornon-transmissive portions are different, when the diameter of at leastone of the light transmissive or non-transmissive portions is set to be5 μm or more, the diameter of the other light transmissive ornon-transmissive portions may be below 5 μm.

[0093] The reason is that when the plane shapes of all the lighttransmissive or non-transmissive portions are circles or polygons have adiameter below 5 μm, the obtained light reflective film excessivelyscatters light, and reflects the light in a small degree. However, whenthe diameters of the light transmissive or non-transmissive portions areexcessively large, the light scattering is reduced, thus causing theoccurrence of an interference fringe.

[0094] In case that the light transmissive or non-transmissive portionsare separately arranged on the mask, preferably, the pitch therebetweenis any value within the range of 3.5 to 30 μm.

[0095] The reason is that when the pitch of the light transmissive ornon-transmissive portions is below 3.5 μm, independency of the lighttransmissive or non-transmissive portions is sometimes decreased. On theother hand, when the pitch of the light transmissive or non-transmissiveportions exceeds 30 μm, randomness of the arranged light transmissive ornon-transmissive portions is sometimes decreased.

[0096] Accordingly, more preferably, the pitch of the light transmissiveor non-transmissive portions of the mask is any value within the rangeof 5 to 20 μm, and most preferably, 7 to 15 μm.

[0097] The pitch of the light transmissive or non-transmissive portionsof the mask denotes the center-to-center distance of neighboring lighttransmissive or non-transmissive portions, and is the mean valueobtained by measuring 10 or more areas. In case that the lighttransmissive or non-transmissive portions of the mask overlap eachother, the pitch is set to be smaller than the above value by severalmicrometers.

[0098] (3) Kind

[0099] Preferably, 2 to 10 kinds of light transmissive ornon-transmissive portions are obtained by varying the diameters of thelight transmissive or non-transmissive portions of the mask.

[0100] This is because it is possible to more efficiently manufacturethe light reflective film with reduced occurrence of the interferencefringe by providing such light transmissive or non-transmissive portionsof different diameters. When the light reflective film is manufacturedusing such a mask, since the light transmissive or non-transmissiveportions are more diversely arranged, it is possible to properly scatterlight. Accordingly, in case that this light reflective film is used inliquid crystal display devices, it is possible to further effectivelyprevent the occurrence of the interference fringe.

[0101] Pattern combinations of the mask including the light transmissiveor non-transmissive portions of different diameters are as follows:

[0102] 1) A hexagonal pattern of 7.5 μm and a hexagonal pattern of 9 μmare combined,

[0103] 2) A hexagonal pattern of 5 μm, a hexagonal pattern of 7.5 μm,and a hexagonal pattern of 9 μm are combined, or

[0104] 3) A regular square pattern of 4.5 μm, a regular square patternof 5 μm, a hexagonal pattern of 7.5 μm, a hexagonal pattern of 9 μm, anda hexagonal pattern of 11 μm are combined.

[0105] (4) Area Ratio

[0106] Preferably, the area ratio of the light transmissive ornon-transmissive portions to the total area of the mask is any valuewithin the range of 10 to 60%.

[0107] The reason is that when the area ratio is below 10%, inmanufacturing the light reflective film, the area occupied by theconcave portions or convex portions is reduced, thereby increasing theproportion of flat portions. Accordingly, the light scattering isremarkably reduced. When the area ratio exceeds 60%, the size of theflat portions is also increased, so the light scattering is remarkablyreduced.

[0108] Accordingly, more preferably, the area ratio of the lighttransmissive or non-transmissive portions to the total area of the maskis any value within the range of 15 to 50%, and most preferably, 20 to40%.

[0109] In case that a positive-type resin is used as the photosensitiveresin for forming the base, a part of the resin on which light havingpassed the light transmissive portions is radiated, is photolyzed andbecomes soluble in a developing agent, so the area ratio of the lightpermeable portions causes trouble. In case that a negative-type resin isused as the photosensitive resin, a part of the resin on which lighthaving passed the light transmissive portions is radiated, isphoto-cured and becomes insoluble in the developing agent, so the arearatio of the light transmissive portions causes trouble.

[0110] 2. Random arrangement

[0111] (1) First Random Arrangement

[0112] In the first embodiment, as shown in FIG. 1, the lighttransmissive and non-transmissive portions are randomly arranged in theplane direction in 100 to 2,000 RGB dot units or a whole screen unit.

[0113] The reason is that when the number of the RGB dots in one unit isbelow 100, and the light reflective film is formed and used in theliquid crystal display device, stains having various shapes are seen.This is also because when the number of the RGB dots in one unit isbelow 100, the occurrence of the interference fringe is insufficientlysuppressed.

[0114] However, when the number of RGB dots exceeds 2,000, the amount ofinformation regarding the random patterns is excessively increased, andsometimes it is difficult to manufacture the mask. Accordingly, morepreferably, the light transmissive and non-transmissive portions arerandomly arranged in the plane direction in 300 to 1,500 RGB dot units,and most preferably 500 to 1,200 RGB dot units.

[0115] Table 1 below illustrates the relationship among the number ofRGB dots of one unit, arrangement characteristics of the lighttransmissive or non-transmissive portions of the mask, and occurrence ofinterference fringe and visibility of stains when the obtained lightreflective film is used in a liquid crystal display device.

[0116] Namely, in Table 1, the leftmost column shows the number of theRGB dots in one unit, i.e., 1 to 11,664. Results are obtained bycomparatively estimating the occurrence of the interference fringe andthe visibility of the stains in the liquid crystal display device incases of the random and regular arrangements of the light transmissiveor non-transmissive portions.

[0117] With reference to the obtained results, in case that the numberof the RGB dots in one unit is comparatively large, for example, 192 to11,664, the random arrangement of the light transmissive ornon-transmissive portions suppresses the occurrence of the interferencefringe and reduces the visibility of the stains.

[0118] In case that the number of the RGB dots in one unit iscomparatively small, for example, 1 to 48, the suppression effect of theoccurrence of the interference fringe is slightly decreased but thevisibility of the stains is sometimes remarkably increased.

[0119] On the other hand, that the regular arrangement of the lighttransmissive or non-transmissive portions does not generate the stains,but remarkably generates interference fringes regardless of the numberof RGB dots in one unit.

[0120] Accordingly, it can be said that in order to suppress theoccurrence of the interference fringe and reduce the visibility of thestains, it is effective to randomly arrange the light transmissive andnon-transmissive portions in the plane direction in 100 to 2,000 RGB dotunits. TABLE 1 Random arrangement Regular arrangement Number ofInterference Interference RGB dots fringe Stain fringe Stain 1 ++ +++++ + 3 ++ ++ ++++ + 6 + ++++ ++++ + 12 + +++ ++++ + 48 + +++ ++++ +192 + + ++++ + 972 + ++ ++++ + 11,664 + + ++++ + Estimation Interferencefringe/Stain + almost invisible level ++ somewhat visible level +++clearly visible level ++++ remarkably visible level

[0121] (2) Second Random Arrangement

[0122] In constructing the mask of the present invention, as shown inFIGS. 2 to 4, preferably, a random pattern of light transmissive ornon-transmissive portions for 3 to 12 RGB dots is randomly arrangedafter being divided or as it is to form the light transmissive ornon-transmissive portions in 100 to 2,000 RGB dot units or the wholesurface unit.

[0123] Thereby, the required information regarding the patterns of thelight transmissive portions of the light non-transmissive portions iscomparatively reduced, and the mask having a large size of area iseasily formed in a short time by repeating the prepared random patternfor 3 to 12 RGB dots.

[0124] In dividing the random pattern for 3 to 12 RGB dots of the lighttransmissive or non-transmissive portions as shown in FIGS. 2 to 4, therandom pattern may be arbitrarily divided, or may be divided withoutarbitrary factors by using a random function or the like.

[0125] (3) Third Random Arrangement

[0126] In constituting the mask of the present invention, as shown inFIG. 5, preferably, a stripe-shaped random pattern of one row or onecolumn is formed and repeated in a plurality of lines to obtain thelight transmissive or non-transmissive portions 244.

[0127] This is because by forming the stripe-shaped random pattern inany one row or column and repeating it appropriately, it is possible toeffectively prevent the occurrence of the interference fringe due to thelight reflective film, and it is also possible to design random patternsin a short time with desirable reflectivity as a whole based on smallamount of information. For example, a mask for an LCD panel of 17 inchesis equally divided in the horizontal direction by n (n is a naturalnumber within the range of 2 to 1,000), the light transmissive ornon-transmissive portions in the 1/n mask are allocated by using arandom function, and such an operation is repeated n times, it ispossible to obtain a random mask pattern for effectively preventing theoccurrence of the interference fringe.

[0128] Moreover, it is possible to obtain the random patterns ofdesirable reflectivity as a whole with good reproducibility by repeatinga predetermined unit of the random pattern in the horizontal or verticaldirection.

[0129] Second Embodiment

[0130] In a second embodiment of the present invention, as shown in FIG.6, there is provided a substrate 70 provided with a light reflectivefilm including a base 77 and a reflective layer 72. A plurality ofconvex portions 76 formed on the surface of the base 77 are randomlyarranged in the plane direction in 100 to 2,000 RGB dot units or a wholescreen unit. Herein, for example, a negative type photosensitive resinis used.

[0131] 1. Base

[0132] As shown in FIG. 6, preferably, the base 77 includes a first base76 and a second base 79 formed over the first base 76. The first base 76includes a plurality of separated (independent) or partially overlappedconvex portions, and the second base 79 is a continuous layer.

[0133] Thereby, it is possible to form a reflective layer 72 with acomparatively gently curved surface by disposing the continuous secondbase 79 on the first base 76. Accordingly, when the substrate 70provided with the reflective layer 72 is used in liquid crystal displaydevices, etc., it is possible to effectively prevent the occurrence ofthe interference fringe. In case that the base includes the first andsecond bases, a plurality of the concave portions or convex portions onthe base generally mean the concave portions or convex portions formedon the first base.

[0134] Hereinafter, as shown in FIG. 6, the base 77 including the firstbase 76 and the second base 79 formed from the bottom is described as apreferred example.

[0135] (1) First Base

[0136] Preferably, the heights of the convex portions or the depths ofthe concave portions of the first base are any value within the range of0.5 to 5 μm.

[0137] The reason is that when the heights of the convex portions or thedepths of the concave portions are below 0.5 μm, it is sometimesdifficult to form the reflective layer with proper curved surface usingthe second base. On the other hand, when the heights of the convexportions or the depths of the concave portions exceed 5 μm, theunevenness of the reflective layer is increased, thereby causing thereflective layer to excessively scatter light, and causing wirebreakages.

[0138] Accordingly, more preferably, the heights of the convex portionsor the depths of the concave portions are any value within the range of0.8 to 4 μm, and most preferably, 1 to 3 μm.

[0139] (2) Second Base

[0140] Preferably, the heights of the continuous convex portions or thedepths of the continuous concave portions are any value within the rangeof 0.1 to 3 μm.

[0141] The reason is that when the heights of the convex portions or thedepths of the concave portions are below 0.1 μm, it is difficult to formthe reflective layer with proper curved surface. On the other hand, whenthe heights of the convex portions or the depths of the concave portionsexceed 3 μm, the unevenness of the reflective layer formed thereon isincreased, thereby causing the reflective layer to excessively scatterlight, and causing wire breakages.

[0142] Accordingly, more preferably, the heights of the convex portionsor the depths of the concave portions are any value within the range of0.1 to 2 μm, and most preferably, 0.3 to 2 μm.

[0143] (3) A Plurality of Concave Portions or Convex Portions

[0144] {circle over (1)} First Random Arrangement

[0145] A plurality of concave portions or convex portions formed on thesurface of the base, particularly, a plurality of concave portions orconvex portions constituting the first base are randomly arranged in theplane direction in 100 to 2,000 RGB dot units or the whole surface unit.

[0146] The reason is that when regularly formed concave portions orconvex portions are employed in liquid crystal display devices, etc., aninterference fringe occurs, thereby deteriorating display quality. Inaddition, when a plurality of concave portions or convex portions arerandomly arranged in the plane direction in predetermined RGB dot units,if the number of the RGB dots in one unit is below 100, stains havingvarious shapes are clearly visible in the liquid crystal displaydevices, etc. with such a substrate.

[0147] Accordingly, more preferably, the light transmissive andnon-transmissive portions are randomly arranged in the plane directionin 300 to 1,500 RGB dot units, and most preferably 500 to 1,200 RGB dotunits.

[0148] Preferably, the heights of the convex portions or the depths ofthe concave portions are the substantially equal to each other. Asdisclosed in Japanese Unexamined Patent Application Publication Nos.6-27481 and 11-281972, this is because when the heights of the convexportions or the depths of the concave portions are different, it isdifficult to manufacture the base provided with these portions and toreliably suppress the occurrence of the interference fringe.

[0149] {circle over (2)} Planar Shape of Convex or Concave Portion

[0150] Preferably, the planar shapes of the concave portions or convexportions formed on the base are circles or polygons, which are arrangedseparately from each other or partially overlapped with each other, oreither thereof.

[0151] The reason is that by making the plane shapes in this way, it ispossible to precisely control the planar shapes and the arrangedpatterns of the concave portions or convex portions using an exposureprocess. The reason is also that it is possible to properly scatterlight so as to effectively prevent the occurrence of an interferencefringe.

[0152] As a preferred example of the planar shape of the convex orconcave portion, FIG. 7(a) shows an offset oval shape (tear drop shape)and FIG. 7(b) shows an offset rectangular shape (oblique pyramid shape).FIGS. 17 to 21 show an oval dome shape, a tear drop shape, an obliquepyramid shape, a rectangular trough shape and a pyramid shape,respectively.

[0153] The reason is that by making the planar shapes of the concaveportions or convex portions asymmetric in this way, together withinclined planes in the height direction, the optical directivity can beimproved while maintaining a designated light scattering property, asshown in FIG. 8. In FIG. 8, dotted line a denotes the amount of observedlight in the case of offset oval shape shown in FIG. 7(a), and solidline b denotes the amount of observed light in the case of unoffsetcircular shape. In case that the concave portions or convex portions areviewed from a designated direction, for example, at a position of theangle +15°, the amount of light incident on the viewer's eyes isincreased by the above-described asymmetrical planar shape. Accordingly,a bright image can be observed by a viewer at the above position.

[0154] {circle over (3)} Diameter of Concave Portion or Convex Portion

[0155] Preferably, the diameters of a plurality of the concave portionsor convex portions formed on the base are any value within the range of3 to 15 μm.

[0156] The reason is that it is possible to precisely control the planarshapes and the arranged patterns of the concave portions or convexportions using the exposure process. The reason is also that it ispossible to properly scatter light and effectively prevent theoccurrence of the interference fringe. Moreover, it is possible toreduce the visibility of the stains of irregular shapes.

[0157] Accordingly, more preferably, the diameters of the concaveportions or convex portions formed on the base are any value within therange of 5 to 13 μm, and most preferably, 6 to 12 μm.

[0158] In addition, preferably, plural, for example, 2 to 10 kinds ofconcave portions or convex portions are obtained by varying theirdiameters. The reason is that it is possible to perform complicatedoptical reflection, which cannot be obtained by using one kind of theconcave portions or convex portions, thereby more effectively scatteringlight. Accordingly, it is possible to effectively prevent the occurrenceof the interference fringe by providing a plurality of the concaveportions or convex portions of different diameters.

[0159] {circle over (4)} Height of Convex Portion or Depth of ConcavePortion

[0160] Preferably, the heights of the convex portions or the depths ofthe concave portions are any value within the range of 0.1 to 10 μm.

[0161] The reason is that when the heights of the convex portions or thedepths of the concave portions are below 0.1 μm, the unevenness of thesubstrate is reduced even using the exposure process, therebydeteriorating the light scattering characteristics. On the other hand,when the heights of the convex portions or the depths of the concaveportions exceeds 10 μm, the unevenness of the substrate is increased,thereby excessively scattering light or causing wire breakages.

[0162] Accordingly, more preferably, the heights of the convex portionsor the depths of the concave portions are any value within the range of0.2 to 3 μm, and most preferably, 0.3 to 2 μm.

[0163] (4) Opening

[0164] Preferably, openings for partially passing light therethrough areformed on the light reflective film. Thereby, it is possible to allowthe light reflective film to be used in transflective type liquidcrystal display devices, etc.

[0165] As shown in FIG. 9, an opening 102 is formed on a part of thelight reflective film 100. Accordingly, external light can beeffectively reflected by a light reflective film 100, and light from theinside can be also effectively emitted to the outside through theopening 102.

[0166] The size of opening 102 is not particularly limited, but may bevariably modified according to the use of the light reflective film. Forexample, assuming that the size of the light reflective film is 100%,preferably, the total size of the openings is any value within the rangeof 5 to 80%, more preferably 10 to 70%, and most preferably 20 to 60%.

[0167] 2. Reflective Layer

[0168] (2) Thickness

[0169] Preferably, the thickness of the reflective layer of the lightreflective film is any value within the range of 0.05 to 5 μm.

[0170] The reason is that when the thickness of the reflective layer isbelow 0.05 μm, the light reflection effect is remarkably reduced. On theother hand, when the thickness of the reflective layer exceeds 5 μm, theflexibility of the obtained light reflective film is reduced, andthereby the manufacturing time of the light reflective film is sometimesprolonged.

[0171] Accordingly, more preferably, the thickness of the reflectivelayer of the light reflective film is any value within the range of 0.07to 1 μm, and most preferably, 0.1 to 0.3 μm.

[0172] (2) Kind

[0173] The material of the reflective layer is not particularly limited.For example, the reflective layer is made of a metal having excellentconductivity and optical reflectivity such as aluminum (Al), silver(Ag), copper (Cu), gold (Au), chromium (Cr), tungsten (W), nickel (Ni),etc.

[0174] It is also preferred that a transparent electrode material suchas Indium Tin Oxide (ITO) or indium oxide, or tin oxide is used on thereflective layer.

[0175] However, in using these metal materials and transparentconductive materials, if they merge in the liquid crystal, preferably,an electrical insulating film is formed on the surface of the reflectivefilm made of such metal material, an electrical insulator is preferablysputtered together with the metal material on the reflective film.

[0176] (3) Base Layer

[0177] In forming the reflective layer on the second substrate,preferably, a base layer having the thickness of 0.01 to 2 μm is formedon the second substrate so as to improve the attachment of thereflective layer and the second substrate and form a smoothly curvedsurface of the reflective layer.

[0178] Material of the base layer includes a single or combination oftwo or more components such as a silane coupling agent, a titaniumcoupling agent, an aluminum coupling agent, an aluminum-magnesium alloy,an aluminum-silane alloy, an aluminum-copper alloy, and analuminum-manganese alloy, an aluminum-gold alloy, etc.

[0179] (4) Mirror Reflectivity

[0180] Preferably, the mirror reflectivity in the reflective layer isany value within the range of 5 to 50%.

[0181] The reason is that when the mirror reflectivity of the reflectivelayer is below 5%, and the reflective layer is used in liquid crystaldisplay devices, etc., the brightness of an obtained display image issometimes remarkably reduced. On the other hand, when the mirrorreflectivity of the reflective layer exceeds 50%, the light scatteringis reduced so that background reflects or external light is excessivelyreflected by the reflective layer.

[0182] Accordingly, more preferably, the mirror reflectivity of thereflective layer is any value within the range of 10 to 40%, and mostpreferably, 15 to 30%.

[0183]3. Combination with Other Constitutional Members

[0184] Preferably, the above-described light reflective film is combinedwith other constitutional members, for example, a color filter 150, alight-shielding layer 151, an overcoat layer 157, a plurality oftransparent electrodes 154, and an orientation film, as shown in FIGS.13 and 14.

[0185] Such combination makes it possible to effectively provide membersof color liquid crystal display devices, etc., with reduced occurrenceof interference fringes. For example, by combining with the colorfilters 151 of a stripee-type, mosaic-type, or delta-type arrangement ofthree chrominance components of RGB (red, green, and blue), colorizationis easily realized. Further, in combination with the light-shieldinglayer 151, it is possible to obtain an image having an excellentcontrast. The light reflective film can be also used as a reflectiveelectrode, however, by providing other electrodes, for example, thetransparent electrode 154, it becomes possible to avoid the influence ofthe reflective film due to the plurality of the concave portions orconvex portions while preventing light absorption.

[0186] Further, preferably, the color filter is formed by threechrominance components of YMC (yellow, magenta, and cyan). Such a colorfilter is excellent in light transmittance and can achieve a brighterdisplay when used in a reflective-type liquid crystal display device.

[0187] Third Embodiment

[0188] In a third embodiment, there is provided a method formanufacturing a light reflective film including a base and a reflectivelayer. The method comprises the steps of: (a) forming a first baseincluding a plurality of concave portions or convex portions byperforming an exposure process on an applied photosensitive resin usinga mask in which light transmissive or non-transmissive portions arerandomly arranged in the plane direction in 100 to 2,000 RGB dot unitsor a whole screen unit; (b) forming a second base including a pluralityof continuous concave portions or convex portions by applying aphotosensitive resin on the surface of the first base and subsequentlyperforming an exposure process on the applied photosensitive resin; and(c) forming a reflective layer on the surface of the second base.

[0189] Hereinafter, with reference to FIGS. 10 and 11, the method formanufacturing the light reflective film (the substrate with the lightreflective film), in which convex portions are formed on the surface ofthe first base, is described in detail. FIG. 10 is a schematic viewillustrating the-process for manufacturing the light reflective film,and FIG. 11 is a flow chart of such a manufacturing process.

[0190] 1. Step of Forming First Base

[0191] Preferably, a plurality of concave portions or convex portionswhich are randomly arranged in the plane direction are formed from aphotosensitive resin by the exposure process using the mask as describedin the first embodiment.

[0192] That is, the randomly arranged concave portions or convexportions are formed from a photosensitive resin, for example, apositive-type photosensitive resin, using the mask in which the lighttransmissive or non-transmissive portions having separate or partlyoverlapped circular and polygonal planar shapes, or either thereof arerandomly arranged.

[0193] (1) Photosensitive Resin

[0194] The kind of photosensitive resin constituting the first base isnot particularly limited. For example, the photosensitive resin may besingle or a combination of two or more of acryl-based resin, epoxy-basedresin, silicon-based resin, phenol-based resin, oxetane-based resin,etc.

[0195] Preferably, an inorganic filler such as silica particles,titanium oxide, zirconium oxide, aluminum oxide, etc. is added to thephotosensitive resin to thereby achieve precisely a designated shapesuch as a circle or a polygon.

[0196] Incidentally, as described above, there are two types ofphotosensitive resins allowed to be used for forming the first base; apositive-type resin, light radiated area of which is photolyzed andbecomes soluble in a developing agent, and a negative-type resin, lightradiated area of which is photo-cured and becomes insoluble in thedeveloping agent. Both types of photosensitive resins can be suitablyused.

[0197] (2) Exposure Process

[0198] As shown in FIG. 10(a) and at step P31 of FIG. 11, in forming afirst base 112, preferably, a photosensitive resin constituting thefirst base is applied uniformly on a supporting portion 114 using a spincoater, or the like to form a first layer 110. Here, preferably, thespin coater is operated under the condition of 600 to 2,000 rpm for 5 to20 seconds.

[0199] Next, in order to improve resolution, as shown at step P32 ofFIG. 11, the first layer 110 is preferably pre-baked. Here, preferably,the first layer 110 is heated using a hot plate at the temperature of 80to 120° C. for 1 to 10 minutes.

[0200] Next, as shown in FIG. 10(b) and at step P33 of FIG. 11,preferably, the first base 112 including the separated or partiallyoverlapped concave portions or convex portions randomly arranged isformed by an exposure process using the mask 119 of the firstembodiment. That is, the mask 119 of the first embodiment is put on thefirst layer 110 made of the uniformly applied photosensitive resin, andthen is preferably exposed to an i-ray, for example. Here, preferably,the exposure to the i-ray, etc. is any value within the range of 50 to300 mJ/cm².

[0201] Then, as shown in FIG. 10(c) and at step P34 of FIG. 11, adevelopment process, for example a positive development process, using adeveloping agent is carried out to obtain the first base 112 includingthe concave portions or convex portions, which are randomly arrangedseparately from each other or partially overlapped with each other.

[0202] It is also preferable that, prior to the formation of a secondbase 113, as shown at step P35 of FIG. 11, a post-exposure process isperformed on the whole surface of the first base 112 with exposure of,for example, 300 mJ/cm², and then a post-baking is performed on thefirst base 112 by heating it at the temperature of 220° C. for 50minutes, thereby further hardening the first base 112.

[0203] 2. Step of Forming Second Base

[0204] At the step of forming the second base, the second base as acontinuous layer is formed on the first base, i.e., on the randomlyarranged convex portions, by applying a resin, etc.

[0205] (1) Photosensitive Resin

[0206] The kind of the photosensitive resin constituting the second baseis not particularly limited. For example, the photosensitive resin maybe a single or a combination of two or more of acryl-based resin,epoxy-based resin, silicon-based resin, phenol-based resin, etc.

[0207] In order to improve the attachment between the first and secondbases, preferably, the first and second bases are made of the same kindphotosensitive resin.

[0208] Further, in order to improve the attachment between the first andsecond bases, a treatment using a silane coupling agent, etc. ispreferably performed on the surface of the first base.

[0209] (2) Exposure Process

[0210] As shown in FIG. 10(d) and at steps P37 to P40 of FIG. 11,preferably, the second base 113 is formed by applying the photosensitiveresin, and exposing the resin at a mounting area around a panel displayarea to an i-ray, etc., to remove the resin layer. Here, like theexposure process of the first base 112, preferably, the exposure to ani-ray, etc. is any value within the range of 50 to 300 mJ/cm².

[0211] As shown at steps P41 and P42 of FIG. 11, after the formation ofthe second base 113, preferably, a post-exposure process is performed onthe whole surface of the second base 113 with the exposure of 300mJ/cm², for example. Then, the second base 113 is post-baked by heatingit at the temperature of 220° C. for 50 minutes, thereby hardening thefirst and second bases 112, 113.

[0212] 3. Step of forming reflective layer

[0213] As shown in FIG. 10(e) and at steps P43 and P44 of FIG. 11, thereflective layer 116 having a smoothly curved surface is formed on thesurface of the second base 113 so that light is properly scattered bythe reflective layer 116.

[0214] (1) Material of Reflective Layer

[0215] As described in the second embodiment, preferably, a metal havingexcellent light reflectivity such as aluminum (Al) and silver (Ag) isused as the material of the reflective layer.

[0216] (2) Forming Method

[0217] Preferably, the reflective layer is formed using a sputteringmethod, etc. Herein, the reflective layer material located at otherareas except a desired area can be removed by a photo-etching method,etc.

[0218] Since the surface of the second base is uneven, in case that thedeposited reflective layer material has a non-uniform thickness, arotational evaporation method or a rotational sputtering method ispreferably employed.

[0219] Preferably, when the reflective layer is formed, the reflectivelayer is electrically connected to terminals of a TFT (Thin FilmTransistor) and a MIM (Metal Insulating Metal), etc.

[0220] Fourth Embodiment

[0221] In a fourth embodiment of the present invention, there isprovided an active matrix type liquid crystal display device using a TFD(Thin Film Diode) which is a diode-type active element as an activeelement. The active matrix liquid crystal display device comprises aliquid crystal element sandwiched between two substrates, and asubstrate with a light reflective film attached to the substrateprovided opposite to the viewing side of the liquid crystal element. Thesubstrate with the light reflective film includes a base and a lightreflective layer. A plurality of concave portions and convex portionsformed on the base are randomly arranged in 100 to 2,000 RGB dot unitsor a whole screen unit.

[0222] Hereinafter, with reference to FIGS. 22 to 24, there will beexemplarily described in detail a transflective type liquid crystaldisplay device which can selectively perform a reflective display usingexternal light and a transmissive display using an illuminator.

[0223] In accordance with the fourth embodiment of the presentinvention, as shown in FIG. 22, a liquid crystal display device 230 isformed by attaching a first substrate 231 a and a second substrate 231 bto each other using a sealant (not shown) applied at their perimeters,and subsequently injecting a liquid crystal into a gap, i.e., a cellgap, surrounded by the first substrate 231 a, the second substrate 23 aband the sealant. Preferably, a liquid crystal activating IC (not shown)is mounted directly on the surface of the second substrate 231 b, forexample, by COG (Chip on Glass) method.

[0224]FIG. 22 shows an enlarged cross-sectional view illustratingseveral dots among a plurality of display dot constituting one displayarea of the liquid crystal display 230, and FIG. 23 shows across-sectional view illustrating one display dot.

[0225] As shown in FIG. 22, a plurality of pixel electrodes are formedin a dot matrix shape in a row direction of X-X and a column directionof Y-Y within the area of the second substrate 231 b surrounded by thesealant. An electrode is in a stripe-shape formed within the area of thefirst substrate 231 a surrounded by the sealant. Such a stripe-shapedelectrode of the first substrate 231 a is provided opposite to theplurality of the pixel electrodes of the second substrate 231 b.

[0226] A portion surrounded by the stripee-shaped electrode on the firstsubstrate 231 a and one of the pixel electrodes on the second substrate231 b with a liquid crystal therebetween forms one display dot. Adisplay area is constituted by a plurality of the display dots arrangedin a dot matrix shape within the area surrounded by the sealant. Theliquid crystal activating IC applies selectively a scan signal and adata signal to the opposite electrodes within the plurality of displaydots, thereby controlling the orientation of the liquid crystal per adisplay dot. That is, light passing through the liquid crystal ismodulated by controlling the orientation of the liquid crystal.Accordingly, an image such as a character and a number is displayedwithin the display area.

[0227] In FIG. 23, the first substrate 231 a comprises a base 236 a madeof glass, plastic, etc., a light reflective film 231 formed on the innersurface of the base 236 a, a color filter 242 formed on the lightreflective film 231, and a transparent stripee-shaped electrode 243formed on the color filter 242. An oriented film 241 a is formed on thestripee-shaped electrode 243. As an orientation treatment, a rubbingtreatment is performed on the oriented film 241 a. The stripee-shapedelectrode 243 is made of a transparent conductive material such as ITO(Indium Tin Oxide), etc.

[0228] Further, the second substrate 231 b, provided opposite to thefirst substrate 231 a, comprises a base 236 b made of glass, plastic,etc., a TFD (Thin Film Diode) 247 as an active element serving as aswitching element, formed on the inner surface of the base 236 b, and apixel electrode 239 connected to the TFD 247. An orientation film 241 bis formed on the TFD 247 and the pixel electrodes 239. A rubbingtreatment as an orientation treatment on the orientation film 241 b isperformed. The pixel electrode 239 is made of transparent conductivematerial such as ITO (Indium Tin Oxide), etc.

[0229] The color filter 242 of the first substrate 231 a includes afilter element 242 a made of one of various chrominance components suchas R (red), G (green) and B (blue), or Y (yellow), M (magenta), C (cyan)and, etc., at an opposing position to the pixel electrode of the secondsubstrate 231 b. Preferably, the color filter 242 includes a black mask242 b at a position not facing the pixel electrode 239.

[0230] As shown in FIG. 23, the size of the gap, i.e., the cell gap,between the first substrate 231 a and the second substrate 231 b ismaintained by ball-shaped spacers 304 dispersed on the surface of anyone of the two substrates 231 a and 231 b. The liquid crystal isenclosed within such a cell gap.

[0231] Here, the TFD 247, as shown in FIG. 23, includes a first metallayer 244, an insulating layer 246 formed on the surface of the firstmetal layer 244, and a second metal layer 248 formed on the insulatinglayer 246. As such, the TFD 247 has a laminated structure of the firstmetal layer/the insulating layer/the second metal layer, what is calleda MIM (Metal Insulator Metal) structure.

[0232] Further, the first metal layer 244 is made of, for example,tantalum (Ta) or a tantalum (Ta) alloy. In case that the first metallayer 244 is made of a tantalum (Ta) alloy, or elements belonging togroups 6 to 8 in the periodic table, such as tungsten, chromium,molybdenum, rhenium, yttrium, lanthanum, dysprosium are added totantalum as a principal element.

[0233] The first metal layer 244 is formed integrally with a first layer249 a of a line wiring 249. The line wiring 249 is formed in stripeeswith the pixel electrode 239 therebetween. The line wiring 249 serve asa scanning line for providing a scan signal to the pixel electrode 239,or as a data line for providing a data signal to the pixel electrode239.

[0234] The insulating layer 246 is made of, for example, tantalum oxide(Ta₂O₅) obtained by oxidizing the surface of the first metal layer 244by an anodizing method. When the first metal layer 244 is anodized, thesurface of the first layer 249 a of the line wiring 249 is oxidizedsimultaneously. Thereby, a second layer 249 b made of tantalum (Ta) isformed.

[0235] Further, the second metal layer 248 is made of, for example, aconductive material such as chromium (Cr). The pixel electrode 239 isformed on the surface of the base 236 b such that a part of the pixelelectrode 239 is overlapped with the leading end of the second metallayer 248. A base layer made of tantalum oxide, etc., is sometimesformed on the surface of the base 236 b before the first metal layer 244and the first layer 249 a of the line wiring 249 are formed on the base236 b. Such a base layer prevents the first metal layer 244 from beingseparated from the base substrate by heating treatment after thestacking of the second metal layer 248, and prevents impurities frombeing scattered in the first metal layer 244.

[0236] Then, the light reflective film 231, which is formed on the firstsubstrate 231 a, is made of, for example, a metal having lightreflectivity such as aluminum (Al). The light reflective film 231includes openings 241 for transmissive light, formed at a positioncorresponding to each of the pixel electrodes 239 belonging to thesecond substrate 231 b, i.e., display dot. Preferably, elongateddome-shaped mountain or valley portion 80, 84, 180, 190, 200, 210 and220 as shown in FIGS. 17 to 21, for example, are formed on the surfaceof the light reflective film 231 facing the liquid crystal. That is, themountain or valley portions 80, 84, 180, 190, 200, 210, 220 arepreferably arranged such that the X axis along which the line wiringextends is their major axis, and the Y axis which is orthogonal to the Xaxis is their minor axis. Further, it is preferable that the major axisX of the mountain or valley portions 80, 84, 180, 190, 200, 210, 220 isset to be parallel with an end side of the base which extends in thedirection X-X, and the minor axis Y is set to be parallel with an end ofthe base which extends in the direction Y-Y

[0237] The liquid crystal display device 230 of the fourth embodimenthas the above-described structure. In case that the liquid crystaldisplay device 230 performs a reflection type display, as shown in FIG.23, external light from the viewer's side of an external viewer, i.e.,from the second substrate 231 b side, enters the inside of the liquidcrystal display device 230, passes through the liquid crystal, andsubsequently reaches the light reflective film 231. Then, the externallight is reflected by the light reflective film 231, and returned to theliquid crystal (refer to arrow F1 in FIG. 23). By a voltage appliedbetween the pixel electrodes 239 and the stripee-shaped electrode 243,i.e., by a scan signal and a data signal, the orientation of the liquidcrystal is controlled in every display dot unit. Thereby, the reflectedlight provided to the liquid crystal is modulated in every display dotunit, thus allowing an image such as a character and a number to bedisplayed to the viewer.

[0238] On the other hand, in case that the liquid crystal display device230 performs a transmission type display, an illuminator (not shown),i.e., a back light which is located outside the first substrate 231 a,emits light. The emitted light passes through a polarizing plate 233 a,a phase difference plate 232 a, the base 236 a, the opening 241 of thelight reflective film 231, the color filter 242, the electrode 243, andthe orientation film 241 a, and is subsequently provided to the liquidcrystal (refer to arrow F2 in FIG. 23). Thereafter, the transmissiontype display is performed similarly in the reflection type display.

[0239] In the fourth embodiment, since a plurality of concave portionsor convex portions are randomly arranged in the plane of the base of thesubstrate with the light reflective film in 100 to 2,000 RGB dot unitsor the whole screen unit, it is possible to reduce an interferencefringe.

[0240] Further, in the fourth embodiment, as described above, in casethat the three-dimensional shapes of the plurality of concave portionsor convex portions along the X axis and the three-dimensional shapes ofthe plurality of concave portions or convex portions along the Y axisare different from each other, the amount of the light reflected at acertain viewing angle can be reduced while increasing the amount of thelight reflected at other viewing angles. As a result, a viewer can see abrighter image displayed within the display area of the liquid crystaldisplay device at a specific viewing angle in the reflection typedisplay using the light reflective film.

[0241] Fifth Embodiment

[0242] In a fifth embodiment of the present invention, a liquid crystaldisplay device is provided comprising a liquid crystal elementsandwiched between two substrates, and a light reflective film formed ona substrate located at the opposite side to the viewing side of theliquid crystal element. The light reflective film includes a base and areflective layer. A plurality of concave portions or convex portionsformed on the base are randomly arranged in the plane direction in a 100to 2,000 RGB dots units or the whole screen unit.

[0243] Hereinafter, with reference to FIG. 13, a passive matrixreflective-type liquid crystal display device of the fifth embodiment isdescribed in detail. Herein, enlargement scale of each layer and eachmember in the drawings may be different to show them in a recognizablesize.

[0244] 1. Constitution

[0245] As shown in FIG. 13, a liquid crystal display device 140 has aconfiguration such that a first substrate 141 and a second substrate 142facing each other, are attached by a sealant 158, and a liquid crystal144 is injected between the two substrates. A light transmissiveprotective plate 145 is located on the viewing side of the liquidcrystal display device 140. The protective plate 145 is a plate-shapedmember to protect the liquid crystal display device 140 from externalimpact. For example, the protective plate 145 is installed on thehousing of an electronic apparatus with the liquid crystal displaydevice 140. The protective plate 145 is positioned adjacent to thesurface of the first substrate 141 (the substrate located on the viewingside) in the liquid crystal display device 140. This embodiment assumesthe case in which the protective plate 145 made of plastic lies adjacentto the surface of a polarizing plate 146 which is closest to theviewer's side among the components of the first substrate 141. This isadvantageous in terms of easiness and low cost in manufacture, however,it is disadvantages in that fine irregularities are easily formed on thesurface.

[0246] The first substrate 141 and the second substrate 142 of theliquid crystal display device 140 are plate-shaped members made of amaterial having light transmissivity characteristics such as glass,quartz, plastic, etc. A plurality of transparent electrodes 143extending in a designated direction are formed on the inner surface (onthe side of the liquid crystal 144) of the first substrate 141 arrangedon the viewing side. Each transparent electrode 143 is a stripe-shapedelectrode made of a transparent conductive material such as ITO (IndiumTin Oxide). The surface of the first substrate 141 provided with thetransparent electrodes 143 is coated with a orientation film (notshown). The orientation film is a thin film made of an organic materialsuch as polyamide. A rubbing treatment is performed on the orientationfilm so as to determine the orientation of the liquid crystal 144 when avoltage is not applied thereto.

[0247] 2. Light Scattering Film

[0248] The polarizing plate 146 for polarizing incident light in adesignated direction and a scattering layer 147 sandwiched between thefirst substrate 141 and the polarizing plate 146 are formed on the outerside (the side provided opposite to the liquid crystal 144) of the firstsubstrate 141. The scattering layer 147 serves to scatter the lightpassing through the scattering layer 147. The scattering layer 147includes an adhesive agent 148 a for adhering the polarizing plate 146to the first substrate 141, and fine particles 148 b dispersed in theadhesive agent 148 a. For example, as the scattering layer 147, theadhesive agent 148 a is made of, for example, an acrylic or epoxymaterial having the fine particles 148 b made of silica dispersedtherein can be used. The refractivity of the adhesive agent 148 adiffers from that of the fine particle 148 b. The incident light on thescattering layer 147 is refracted at the boundary between the adhesiveagent 148 a and the fine particle 148 b. As a result, it is possible toemit the incident light on the scattering layer 147 scatteredappropriately.

[0249] In the scattering layer 147 of the fifth embodiment of thepresent invention, the number of the fine particles 148 b dispersed inthe adhesive agent 148 a and the refractivities of the fine particles148 b and the adhesive agent 148 are determined such that a Haze value Hof the scattering layer 147 is any value within the range of 10 to 60%.Here, the Haze value H represents the degree of light scattering whenthe incident light on a member passes through the member, and is definedby the below equation.

[0250] Haze Value H=(Td/Tt)×100(%)

[0251] Here, Tt denotes transmittance (%) of whole light, and Td denotestransmittance (%) of scattered light. The transmittance (%) of wholelight, Tt, is the ratio of the amount of light passing through a sample,which is a target of measurement of the Haze value H, to the amount ofincident light on the sample. On the other hand, the transmittance (%)of scattered light, Td, is the ratio of the amount of light emitted intoany direction other than a designated direction (i.e., the amount ofscattered light) to the amount of light passing through the sample incase light is irradiated from a designated direction. That is, assumingthat transmittance (%) of parallel light, Tp, is the ratio of the amountof light emitted from the sample parallel with the incident light, tothe total amount of light emitted from the sample, the abovetransmittance (%) of scattered light, Td, is represented by thedifference between the transmittance (%) of whole light, Tt, and thetransmittance (%) of parallel light, Tp (Td=Tt−Tp). Obviously from theabove, the larger the Haze value H is, the higher the light scatteringdegree is (that is, the ratio of the amount of scattered light to theamount of transmitted light is high). In other words, that the smallerthe Haze value H is, the lower the light scattering degree is (that is,the ratio of the amount of scattered light to the amount of transmittedlight is low). Incidentally, Haze value H is described in detail in JIS(Japanese Industrial Standards) K6714-1977.

[0252] 3. Reflective Layer (Light Reflective Film)

[0253] A reflective layer 149 is formed on the inner surface (on theliquid crystal 144 side) of the second substrate 142. The reflectivelayer 149 serves to reflect incident light on the liquid crystal device140 from the viewing side, and is made of a metal having opticalreflectivity, such as aluminum or silver.

[0254] As shown in FIG. 13, an area of the inner surface of the secondsubstrate 142 coated with the reflective layer 149 has an uneven surfaceincluding a plurality of protrusions and concavities. More specifically,in the light reflective film including the base and the reflective layer149, the plurality of concave portions or convex portions formed on thesurface of the base have substantially the same height or depth. Theplanar shapes of the concave portions or convex portions are circles orpolygons, which are separate from each other or partially overlappedwith each other, or either thereof. The plurality of concave portions orconvex portions are randomly arranged in the plane direction of thereflective layer 149.

[0255] Therefore, the surface of the reflective layer 149 is also unevenbecause of the unevenness of the surface of the second substrate 142including the protrusions and concavities. That is, the reflective layer149 has a light scattering structure enabling the layer 149 to scatterlight appropriately so as to realize a broad viewing angle. Morespecifically, the reflective layer 149 is formed on the base including aplurality of concave portions or convex portions, and the plurality ofconcave portions or convex portions formed on the base havesubstantially the same height or depth. The planar shapes of the concaveportions or convex portions are circles or polygons, which are separatefrom each other or partially overlapped with each other, or eitherthereof. The plurality of concave portions or convex portions arerandomly arranged in the plane direction of the reflective layer 149.

[0256] 4. Other Components

[0257] Further, the color filter 150, the light-shielding layer 151, theovercoat layer 157 for leveling the irregularities formed by the colorfilter 150 and the light-shielding layer 151, a plurality of transparentelectrodes 154, and an oriented film (not shown) are formed on thesurface of the reflective layer 149 coating the second substrate 142.

[0258] Each transparent electrode 154 is a stripe-shaped electrodeextending in the perpendicular direction (in a horizontal direction ofFIG. 13) to the extending direction of the transparent electrodes 143 onthe first substrate 141. In the same manner as the transparent electrode143, each transparent electrode 154 is made of a transparent conductivematerial such as ITO (Indium Tin Oxide).

[0259] In such configuration, the orientation of the liquid crystal 144is changed by a voltage applied between the transparent electrodes 143and the transparent electrodes 154. That is, the area where thetransparent electrodes 143 and the transparent electrodes 154 cross eachother functions as a pixel (sub-pixel). The color filter 150 is a resinlayer provided corresponding to each of such pixels, and is colored inone of R, G, and B using dyes and pigments.

[0260] The light-shielding layer 151 is formed in a lattice-typestructure so as to shield a gap portion between pixels. For example, thelight-shielding layer 151 is made of a black resin material in whichcarbon black is dispersed.

[0261] 5. Operation

[0262] The reflection type display is realized by the above-describedstructure. That is, external light such as sunlight or indoorilluminating light passes through the protective plate 145 to enter theliquid crystal display device 140, and is subsequently reflected by thesurface of the reflective layer 149.

[0263] Such reflected light passes through the liquid crystal 144 andthe first substrate 141 to be properly scattered by the scattering layer147, then passes through the polarizing plate 146 to be emitted to theviewing side of the liquid crystal display device 140. The light emittedfrom the liquid crystal display device 140 passes through the protectiveplate 145 and then is displayed to a viewer.

[0264] As described above, in case that the protective plate 145 is madeof plastic, it is difficult to form a completely flat surface of theprotective plate 145. A plurality of fine concave portions and convexportions are likely formed on the surface of the protective plate 145.In case that such protective plate 145 with the fine concave portionsand convex portions is arranged close to the first substrate 141 of theliquid crystal display 140, when the light emitted from the liquidcrystal display device 140 passes through the protective plate 145, thelight interferes with the protective plate 145. Accordingly,interference fringes corresponding to the concave portions and convexportions are overlapped with a display image, and thereby deteriorationof the display quality may occur.

[0265] However, according to the studies by the present inventors, asshown in the above-described embodiment, when light passes through theliquid crystal 144 and reaches the protective plate 145, the light isscattered by the scattering layer 147 so that a display of high qualitycan be achieved.

[0266] In the constitution of the liquid crystal display device as shownin FIG. 13, in order to reduce the occurrence of the interferencefringe, it is preferable that the Haze value H of the scattering layer147 is set to be large, i.e., to a high degree of light scattering.However, if the Haze value H is too large (for example, 70% or more),light reaching the protective plate 145 from the liquid crystal displaydevice 140 is excessively scattered, there occurs a new problem that thecontrast is decreased, i.e., a display image gets blurred. On the otherhand, if the Haze value H of the scattering layer 147 is too small, forexample, less than 10%, stains due to the concave portions and convexportions are likely to be seen.

[0267] The test results obtained by the present inventors reveal thatwhen the Haze value H of the scattering layer 147 is set to be any valuewithin the range of 10% to 40%, it is possible to prevent the remarkablereduction of contrast of the display image and the deterioration ofdisplay quality caused by the concave portions and convex portionsformed on the surface of the protective plate 145. As a result, gooddisplay quality of the liquid crystal display device is obtained.

[0268] Accordingly, preferably, the Haze value H of the scattering layer147 is set to be in the above range, and more preferably, approximately20%.

[0269] As shown in the fifth embodiment, in case the scattering layer147 including the adhesive agent 148 a and the fine particles 148 bdispersed in the adhesive agent 148 a is used, the Haze value H can beset differently by controlling the amount (the number) of the fineparticles 148 b added to the adhesive agent 148 a.

[0270] That is, if the amount of the fine particles 148 b dispersed inthe adhesive agent 148 a is increased, incident light on the scatteringlayer 147 is scattered more widely so that the Haze value H of thescattering layer 147 is can be raised. On the other hand, the Haze valueH of the scattering layer 147 can be lowered by decreasing the amount ofthe fine particles 148 b added to the adhesive agent 148 a.

[0271] Furthermore, the liquid crystal display device 140 of the fifthembodiment is advantageous in terms of easily setting the scatteringdegree of light emitted from the liquid crystal display device 140within a wide range. That is, in a liquid crystal display device withoutthe scattering layer 147, in order to adjust the scattering degree oflight emitted from the liquid crystal display device, it is necessary toadjust the shape of the surface of the reflective layer 149, forexample, the heights of convex portions and the depths of concaveportions, or the distance between the neighboring convex portions (orconcave portions).

[0272] However, since it requires technical skill to form the desiredshapes of concave portions and convex portions on the second substrate142, it is not always easy to precisely form the desired shape of thesurface of the reflective layer 149. Further, since the adjustable rangeof the scattering degree of light emitted from the liquid crystaldisplay device 140 only by controlling the shape of the surface of thereflective layer 149 is limited, the scattering degree of light has alimited range.

[0273] On the other hand, according to this embodiment, without widelychanging the shape of the surface of the reflective layer 149, thescattering degree of light emitted from the liquid crystal displaydevice 140 can be widely and easily adjusted by changing the Haze valueH of the scattering layer 147, for example, by properly adjusting theamount of the fine particles 148 b dispersed in the adhesive agent 148a. This is also an advantage of this embodiment.

[0274] Sixth Embodiment

[0275] In a sixth embodiment of the present invention, a passive matrixtransflective type liquid crystal display device is provided comprisinga liquid crystal element sandwiched between two substrates, and a lightreflective film formed on a substrate provided opposite to the viewingside of the liquid crystal element. The light reflective film includes abase and a reflective layer. A plurality of concave portions or convexportions formed on the base are randomly arranged in the plane directionin 100 to 2,000 RGB dot units or the whole screen area unit.

[0276] Hereinafter, with reference to FIG. 14, the passive matrixtransflective type liquid crystal display device of the sixth embodimentis described in detail. Herein, the same elements as those of FIG. 13are denoted by the same reference numerals and their detaileddescriptions are omitted.

[0277] 1. Basic Constitution

[0278] As shown in FIG. 14, in the sixth embodiment, a back light unit153 is disposed on the back of a liquid crystal display device 160(located opposite to the viewing side). Such back light unit 153includes a plurality of LEDs 15 (only one LED is shown in FIG. 14)functioning as light sources, a light guide plate 152, a diffusion plate155, and a reflective plate 156. The light guide plate 152 guides lightfrom the LED 15 incident on its side end surface, toward the wholesurface of the second substrate 142 of the liquid crystal display device160. The diffusion plate 155 uniformly diffuses the light guided by thelight guide plate 152 throughout the liquid crystal display device 160.The reflective plate 156 reflects the light which emits from the lightguide plate 152 toward the opposite side to the liquid crystal displaydevice 160, toward the liquid crystal display device 160 side.

[0279] Here, the LED 15 is not always turned on. In case that the liquidcrystal display device 160 is used under no external light, the LED 15is turned on in response to the instruction of a user or the detectionsignal by a sensor.

[0280] Furthermore, in the liquid crystal display device 160 accordingto the sixth embodiment, openings 159 are formed in the reflective layer149 in the areas corresponding to central portions of pixels. Anotherpair pf polarizing plates are attached to the outer side of the secondsubstrate 142 (the side located opposite to the liquid crystal 144).However, such polarizing plates are omitted in FIG. 14.

[0281] 2. Operation

[0282] The liquid crystal display device 160 having the above-describedstructure can perform the transmission type display in addition to thereflection type display described in the fifth embodiment. That is,light irradiated from the back light unit 153 to the liquid crystaldisplay device 160 passes through the openings 159 of the reflectivelayer 149. Such light passes through the liquid crystal 144 and thefirst substrate 141, is scattered by the scattering layer 147, passesthrough the polarizing plate 146, and is subsequently emitted to theviewing side. The transmissive type display is performed by allowing theemitted light to pass through the protective plate 145 and to besubsequently emitted at the viewing side of the liquid crystal displaydevice.

[0283] Accordingly, in this embodiment, like in the fifth embodiment,even when the protective plate 145 including the fine concave portionsand convex portions formed on its surface is located close to the liquidcrystal display device 160, the deterioration of display quality due tothe above uneven surface structure of the protective plate 145 can beprevented.

[0284] Seventh Embodiment

[0285] In a seventh embodiment of the present invention, a modifiedliquid crystal display device is provided comprising a liquid crystalelement sandwiched between two substrates, and a light reflective filmformed on a substrate provided opposite to the viewing side of theliquid crystal element. The light reflective film includes a base and areflective layer. A plurality of concave portions or convex portionsformed on the base is randomly arranged in the plane direction in 100 to2,000 RGB dot units or a whole screen unit.

[0286] (1) First Modification

[0287] Although the scattering layer 147 is sandwiched between the firstsubstrate 141 and the polarizing plate 146 in the above-describedembodiments, the position of the scattering layer 147 may not be limitedthereto. For example, in case that a phase difference plate forcompensating an interference fringe is provided between the polarizingplate 146 and the first substrate 141, the scattering layer 147 may beinserted between the phase difference plate and the first substrate 141,or between the phase difference plate and the polarizing plate 146. Inshort, the scattering layer 147 is only required to be located on theside of the protective plate 145 with reference to the liquid crystal144.

[0288] Furthermore, in the above-described embodiments, the scatteringlayer 147 in which many fine particles 148 b are dispersed in theadhesive agent 148 a is used. However, the constitution of thescattering layer 147 is not particularly limited thereto. The scatteringlayer 147 may have any constitution as long as the layer can scatterincident light. When the scattering layer 147 including the adhesiveagent 148 a is used, members (for example, the first substrate 141 andthe polarizing plate 146 of the above embodiments) by which thescattering layer 147 is sandwiched can be attached to each other by theadhesive agent 148 a. Accordingly, as compared with the scattering layer147 without the adhesive agent 148 a, it is possible to reduce themanufacturing cost and to simplify the manufacturing process, which isadvantageous.

[0289] (2) Second Modification

[0290] The fifth embodiment describes the reflective-type liquid crystaldisplay device, and the sixth embodiment describes the transflectivetype liquid crystal display device. However, the present invention maybe applied to a transmissive type liquid crystal display device whichperforms transmissive type display without the reflective layer 149.That is, the transmission type liquid crystal display device may beformed by removing the reflective layer 149 from the transflective typeliquid crystal display device, as shown in FIG. 14.

[0291] Further, the present invention may be applied to a transflectivetype liquid crystal display device using a half mirror, which passes apart of irradiated light and reflects the remaining part of the light,as a substitute for the reflective layer 149 with the openings 159 ofthe transflective type liquid crystal display device of the fourthembodiment.

[0292] (3) Third Modification

[0293] The above-described embodiments describe the protective plate 145made of the plate-shaped plastic member. The surface of the protectiveplate 145 is likely to form irregularities, so application of theinvention can bring remarkable effects. However, the protective plate145 is not particularly limited to the above material, but may be madeof plate-shaped members of various materials.

[0294] (4) Fourth Modification.

[0295] Although the above-described embodiments describe the case thatthe present invention is applied to a passive matrix liquid crystaldisplay device, the present invention may be applied to an active matrixliquid crystal display device using a diode switching elementrepresented by a TFD (Thin Film Diode) and a triode switching elementrepresented by a TFT (Thin Film Transistor). Further, although theabove-described embodiments describe the case that the color filter 150and the light-shielding layer 151 are formed on the second substrate142, the present invention may be applied to a liquid crystal displaydevice comprising such components formed on the first substrate 141, anda liquid crystal display device without the color filter 150 or thelight-shielding layer 151. Moreover, the present invention may beapplied to the liquid crystal display device 160 with the protectiveplate 145 located close to the viewing side regardless of the conditionsof other components.

[0296] (5) Fifth Modification

[0297] Although the above fourth embodiment describes the active matrixliquid crystal display device using a TFD, a diode active element, as anactive element, the present invention may be applied to an active matrixliquid crystal display device using a TFT, a triode active element, asan active element, as shown in FIG. 13. In this case, as shown in FIG.13, preferably, the TFT element is formed on a shield area.

[0298] Eighth Embodiment

[0299] In an eighth embodiment, there is provided an electronicapparatus including an optical display device comprising a lightreflective film, in which the light reflective film includes a base anda reflective layer, and a plurality of concave portions or convexportions formed on the surface of the base are randomly arranged in theplane direction in 100 to 2,000 RGB dot units or a whole screen unit.

[0300] (1) Mobile Computer

[0301] Now, a mobile personal computer (i.e., a notebook personalcomputer) provided with a display unit employing the liquid crystaldisplay device of the present invention is described. FIG. 15 is aperspective view showing the constitution of such a personal computer.As shown in FIG. 15, a personal computer 161 comprises a main body 163provided with a keyboard 162, and a display unit 164 employing a liquidcrystal display device according to the present invention. The displayunit 164 is constituted such that the liquid crystal display device 160according to the present invention is received in a case 166 providedwith the plastic protective plate 145 corresponding to a window 165.More specifically, the liquid crystal display device 160 is accommodatedin the case 166 such that the substrate surface at the viewing side islocated close to the protective plate 145. In the personal computer 161,in order to obtain display with excellent visibility even underinsufficient external light, the transflective type liquid crystaldisplay device comprising the back light unit 153 on the rear side, asdescribed in the seventh embodiment, is preferably employed.

[0302] (2) Mobile Telephone

[0303] Now, a mobile telephone provided with a display device employinga liquid crystal display device of the present invention is described.FIG. 16 is a perspective view of such a mobile telephone. As shown inFIG. 16, a mobile telephone 170 comprises a plurality of operationbuttons 171, an earpiece 172, a mouthpiece 173, and a display unit 174employing a liquid crystal display device (not shown) of the presentinvention. The mobile telephone 170 is constituted such that the liquidcrystal display device of the present invention is received in a case176 provided with a plastic protective plate 175 corresponding to awindow 174 b. Like the above personal computer, the liquid crystaldisplay device is accommodated in a case 176 such that the substratesurface at the viewing side is located close to the protective plate175.

[0304] Besides the personal computer of FIG. 15 and the mobile telephoneof FIG. 16, the liquid crystal display device of the present inventioncan be employed in electronic apparatus such as liquid crystal TVs, viewfinder-type monitor direct view video tape recorders, car navigationapparatuses, pagers, electronic notes, electronic calculators, wordprocessors, work stations, TV phones, POS terminals, apparatus withtouch panel, etc.

[0305] As apparent from the above description, according to the liquidcrystal display of the present invention, even when a protective platehaving fine irregularities on its surface is located close to thesubstrate surface of the display device, it is possible to prevent thedeterioration of display quality due to the irregularities. Accordingly,it is possible to slim or miniaturize electronic apparatus withoutdeteriorating the display quality.

[0306] Effects of the Invention

[0307] As described above, the mask of the present invention and thelight reflective film obtained therefrom respectively comprise aplurality of light transmissive or non-transmissive portions randomlyarranged in the plane direction in a predetermined number or more of RGBdot units, thereby suppressing the occurrence of stains of irregularshapes and effectively preventing the occurrence of an interferencefringe when the mask and the film are used in liquid crystal displaydevices, etc. Further, since relatively little information aboutpatterns is needed in making the mask, it is possible to easily andrapidly form the mask used for manufacturing the light reflective filmfor even a large-sized liquid crystal display device as well as a smallliquid crystal display device while reducing the occurrence of theinterference fringe.

[0308] The liquid crystal display device and electronic apparatuscomprising the light reflective film of the present invention suppressthe occurrence of stains of irregular shapes, effectively prevent theoccurrence of an interference fringe, and are easy to design andmanufacture.

[0309] Further, in the liquid crystal display device and electronicapparatus comprising the light reflective film of the present invention,even when the protective plate having fine irregularities on its surfaceis located close to the reflective film, deterioration of displayquality due to the irregularities can be prevented.

[0310] The entire disclosure of Japanese Patent Application No.2002-108529 filed Apr. 10, 2002 is incorporated by reference.

What is claimed is:
 1. A mask for manufacturing a substrate with a lightreflective film, wherein light transmissive or non-transmissive portionsare randomly arranged in a plane direction in 100 to 2,000 dot units ora whole screen unit.
 2. The mask according to claim 1, wherein thetransmissive or non-transmissive portions in 100 to 2,000 dot units or awhole screen unit are formed by randomly arranging a prepared randompattern of light transmissive or non-transmissive portions for 3 to 12RGB dots.
 3. The mask according to claim 1, wherein the lighttransmissive or non-transmissive portions are formed by forming astripe-shaped random pattern in a row direction or in a columndirection, and repeating the stripe-shaped random patterns in aplurality of lines.
 4. The mask according to claim 1, wherein a diameterof the light transmissive or non-transmissive portions is any valuewithin the range of 3 to 15 μm.
 5. The mask according to claim 1,wherein the light transmissive or non-transmissive portions havedifferent diameters to form a plurality of kinds of light transmissiveor non-transmissive portions.
 6. A substrate with a light reflectivefilm comprising: a base; and a reflective layer on the base; wherein aplurality of concave portions or convex portions formed on the base arerandomly arranged in a plane direction in 100 to 2,000 RGB dot units ora whole screen unit.
 7. The substrate with the light reflective filmaccording to claim 6, wherein the plurality of concave portions orconvex portions are formed by forming a stripe-shaped random patter ofconcave portions or convex portions in a row direction or in a columndirection, and repeating the stripe-shaped random pattern in a pluralityof lines.
 8. The substrate with the light reflective film according toclaim 6, wherein a diameter of the concave portions or convex portionsis any value within the range of 3 to 15 μm.
 9. The substrate with thelight reflective film according to claim 6, wherein the plurality ofconcave portions or convex portions have different diameters to form aplurality of kinds of concave portions or convex portions.
 10. Thesubstrate with the light reflective film according to claim 6, whereinthe base includes a first base and a second base over the first base,the first base includes a plurality of concave portions or convexportions, and the second base includes a plurality of continuous concaveportions or convex portions.
 11. A method for manufacturing a lightreflective film including a base and a reflective film, comprising thesteps of: (a) forming a first base including a plurality of concaveportions or convex portions by performing an exposure process on anapplied photosensitive resin using a mask in which light transmissive ornon-transmissive portions are randomly arranged in a plane direction in100 to 2,000 dot units or a whole screen unit; (b) forming a second baseincluding a plurality of continuous concave portions or convex portionsby applying a photosensitive resin on the first base and subsequentlyperforming an exposure process on the applied photosensitive resin; and(c) forming a reflective layer on the second base.
 12. An opticaldisplay device comprising: an optical element sandwiched betweensubstrates; and a light reflective film formed on one of the substratesopposite to a viewing side of the optical element, wherein the lightreflective film includes a base and a reflective layer, and a pluralityof concave portions or convex portions formed on the base are randomlyarranged in a plane direction in 100 to 2,000 dot units or a wholescreen unit.
 13. The optical display device according to claim 12,wherein a light scattering film is provided on the substrate at theviewing side of the optical element.
 14. The optical display deviceaccording to claim 12, further comprising a protective plate on theviewing side of the optical element.
 15. An electronic apparatusincluding an optical display device comprising a light reflective film,wherein the light reflective film includes a base and a reflectivelayer, and a plurality of concave portions or convex portions formed onthe surface of the base are randomly arranged in the plane direction in100 to 2,000 dot units or a whole screen unit.